It rarely happens. Yet this night it does. A creature falls
to her death on the shore of a lake, and her body is blanketed by silt and sand.
Her immaculately preserved fossils, eons later, have a story to tell. But how to
decipher them?

The team that found her called her Lucy, after "Lucy in the
Sky with Diamonds," the song they played over and over as they celebrated her
discovery in 1974. Other remarkable fossils of Lucy's species, Australopithecus
afarensis, were later unearthed at other sites. Together, they offer a picture
of one of our earliest human ancestors.

Learn how scientists solve the riddles of ancient bones. Below
are snapshots of four important fossil sites for A. afarensis.